Question: When did the work period start and end for Greg Nickels, the head of government of Seattle?
Paraphrase: When did the work length start and stop for Greg Nickels, the head of government of Seattle?
SPARQL (Wikidata): SELECT ?value1 ?value2 WHERE { wd:Q5083 p:P6 ?s . ?s ps:P6 wd:Q330519 . ?s pq:P2031 ?value1 . ?s pq:P2032 ?value2 }